The Vongola Underground Base (ボンゴレの土地下あじと, Bongore no tochika ajito?) is a secret hideout located under the town of Namimori in Japan. It was commissioned by the future Tsunayoshi Sawada for the Vongola Famiglia. It is connected to the Foundation headquarters via a steel door, but this is rarely used due to the future Hibari's wishes.
There are six entrances to the Base, all camouflaged and protected by a security system. One of the entrances is hidden in a forest, while another is concealed at an abandoned warehouse district. The location of the remaining entrances, and whether said six entrances includes the connection with the Foundation headquarters, is unknown.
There are 16 floors (B1F-B16F), B1F being the floor closest to ground level and B16F being the lowest level. B1-B4F only contain the hatch elevators. The more important facilities are located in the lower levels.
Surveillance cameras scattered all over surface Namimori are also connected to and monitored at this Base. Other Vongola Bases, such as the Varia Headquarters, can contact this Base via a special code.
Some of the Base' amenities include:
- a dojo floor
- an illusions training floor, using Mammon's training program
- Storm Room
- a general training purpose floor (sparring, box weapon testing, inventions testing, etc.)
- a dining hall
- a kitchen
- a laundry room
- sleeping quarters
- power generator rooms
- a conference room
- a vegetable garden floor
- rooms for medical treatment, complete with the latest medical technology and equipment
- separate baths for men and women
After the fall of the Vongola Headquarters, Future Lal Mirch was sent to the 10th Generation Vongola Family in Japan to bring details of the news. She was given a false location of the base, and Future Takeshi Yamamoto was sent out to lead her to the true location. When they rendezvous at an encounter with a Strau Mosca, present Tsuna and present Hayato Gokudera were under Future Lal Mirch's protection. All of them were then taken to the Base, where Future Yamamoto used Kojirou to unveil the entrance.
Future Yamamoto stated that it was the future Tsuna that ordered the construction of the Base. It was intended to be a stronghold, and is only at 60%—the construction presumably halted due to the start of the Vongola Hunt and thus turning it into the last stand of the Vongola's 10th Generation.
Future Lambo and future I-Pin, after the rescue of future Kyoko Sasagawa and Haru Miura, were returning to the Base via the abandoned warehouse district entrance when they were found by Nosaru and Tazaru. They were helped by Future Yamamoto, Tsuna and Gokudera who had exited the same entrance to search for the strongest Guardian, Kyoya Hibari, in Namimori.
The majority of Tsuna and the others' training took place in the Base.
The Base' operations, maintenance, upgrade and repair are mostly overseen by Giannini.